The ever-vigilant Nuclear Regulatory Commission has issued milestone regulations requiring the builders of new nuke reactors to explain how their plants might withstand the crash of large commercial jetliners.

But the NRC has exempted the reactors that matter most—the 104 licensed to operate RIGHT NOW. As you read this, jets hitting any of them could kill untold thousands of us and render entire regions of our nation permanently uninhabitable.

But requiring current reactor owners to do what’s now expected of future ones would apparently be an unsupportable burden.

All reactors would shut immediately without federal limits to their owners’ liability for the incalculable death and destruction that could come from a stricken nuke.

The first jet to crash into the World Trade Center on 9/11/2001 flew DIRECTLY over the one dead and two operating reactors at Indian Point, 45 miles up the Hudson, plus the three spent fuel pools there. Terrorists close to the attack—including Khalid Sheikh Mohammed—have confirmed that reactors were originally targeted, but they changed their minds “for the moment.”

This is the NRC’s first significant public nod to ANY structural responsibility for such a catastrophe.

But the regulations say taxpayers must pay to prevent such attacks, not the industry. So far, not a single US reactor has any form of anti-aircraft protection, federal, state or otherwise, and many doubt they’d work anyway.

After 9/11 a bitter debate raged over the ability of American reactors to withstand jet crashes. Not one was required to do so, most importantly the fragile General Electric Mark I and Mark II designs installed at more than a third of US reactors. “We have not analyzed what would happen if a 767 crashed into a reactor,” according to the Commission’s Neil Sheehan. “Until we’ve done that, we can’t say with certainty that they could withstand it.”

NRC Chairman Dale Klein recently told CNBC a jet would “bounce off” a reactor containment dome. The industry uses a visually dramatic crash of an F-4 Phantom jet into a movable wall at the Sandia National Laboratory to “prove” its containments are “robust.” But the crash test “proves nothing, since the wall was not attached to the ground and was displaced nearly six feet,” says the Nuclear Control Institute’s Scientific Director Bernard Lyman. The Sandia test report says “the major portion of the impact energy went into movment of the target and not in producing structural damage.” The Phantom’s fuel tanks were filled with water, not jet fuel, and its total weight was about 5% of a 767. The wall was 12 feet thick, as opposed to 3.5 for a reactor containment dome.

Crash tremors at existing reactors could easily compromise cooling, electrical, safety, communication and other critical components without a containment breach. Human operators have not been realistically trained to run a control room after surviving—maybe—the impact’s shock waves.

As at Three Mile Island, radiation can—and does—escape en masse from stacks, outtake pipes and elsewhere around the reactor structure with no containment breach. Nobody knows what prolonged jet fuel fires would do to the already super-heated cores and cooling water.

Nearby pools and dry casks overbrimming with immensely radioactive used fuel rods are sitting ducks. Some are inside the containments. But most sit open to small-scale attack, let alone a jet crash.

The core radiation inside American commercial reactors can exceed by a thousand-fold what was released at Hiroshima and Nagasaki.

After a half-century of operation, eight years after 9/11, the official NRC admission that jets crashing into future reactors demand a structural response is long overdue. It confirms that every atomic power plant is a potential target for terror and error, a pre-deployed weapon of radioactive mass destruction.

“President Obama should replace the Bush-appointed Chairman of the NRC with an individual who will address the threat rather than lie about the vulnerability of nuclear reactors and their wastes to terrorist attack,” says Greenpeace’s Jim Riccio.

At very least the new administration should demand that the new regulations for proposed new reactors must now be applied to the ones actually operating.